refactor: we don't wanna export pkg/oonimkall/tasks (#216)

* doc: merge the engine and the cli readmes

Part of https://github.com/ooni/probe/issues/1335

* refactor: we don't wanna export pkg/oonimkall/tasks

See https://github.com/ooni/probe/issues/1335

pkg/oonimkall/internal/tasks/event.go

@@ -0,0 +1,57 @@
+package tasks
+
+type eventEmpty struct{}
+
+// EventFailure contains information on a failure.
+type EventFailure struct {
+	Failure string `json:"failure"`
+}
+
+// EventLog is an event containing a log message.
+type EventLog struct {
+	LogLevel string `json:"log_level"`
+	Message  string `json:"message"`
+}
+
+type eventMeasurementGeneric struct {
+	Failure string `json:"failure,omitempty"`
+	Idx     int64  `json:"idx"`
+	Input   string `json:"input"`
+	JSONStr string `json:"json_str,omitempty"`
+}
+
+type eventStatusEnd struct {
+	DownloadedKB float64 `json:"downloaded_kb"`
+	Failure      string  `json:"failure"`
+	UploadedKB   float64 `json:"uploaded_kb"`
+}
+
+type eventStatusGeoIPLookup struct {
+	ProbeASN         string `json:"probe_asn"`
+	ProbeCC          string `json:"probe_cc"`
+	ProbeIP          string `json:"probe_ip"`
+	ProbeNetworkName string `json:"probe_network_name"`
+}
+
+// EventStatusProgress reports progress information.
+type EventStatusProgress struct {
+	Message    string  `json:"message"`
+	Percentage float64 `json:"percentage"`
+}
+
+type eventStatusReportGeneric struct {
+	ReportID string `json:"report_id"`
+}
+
+type eventStatusResolverLookup struct {
+	ResolverASN         string `json:"resolver_asn"`
+	ResolverIP          string `json:"resolver_ip"`
+	ResolverNetworkName string `json:"resolver_network_name"`
+}
+
+// Event is an event emitted by a task. This structure extends the event
+// described by MK v0.10.9 FFI API (https://git.io/Jv4Rv).
+type Event struct {
+	Key   string      `json:"key"`
+	Value interface{} `json:"value"`
+}